Shapes inside setup() are not rendered

[arihantparsoya]

The shapes called inside the setup() are not rendered on the canvas.

To Reproduce

from p5 import *

def setup():
    size(100, 100)
    background(255)
    rect((0, 0), 50, 50)
    no_stroke()

def draw():
	return

if __name__ == '__main__':
  run()

Expected behavior
The rectangle should be rendered on the canvas (output from p5py)

Output from p5py

[tushar5526]

Shapes inside setup are drawn correctly if you remove size(100, 100) in setup()
Maybe, the shape rect((0,0),50) is drawn on default canvas of 360 * 360 but size(width,height) in setup() is overwiting and clearing the default canvas, so it shows nothing

[tushar5526]

@parsoyaarihant @jeremydouglass , size() is not implemented correctly, background (250) rect((0, 0), 50, 50) no_stroke() are drawn on the default canvas first which is of size 360 by 360, then size() is called which removes everything

I tried tracing the callbacks
size() changes the builtins.width and builtins.height, then some event calls on_resize() in base.py which then changes the canvas, this event should be called first before drawing the background(...) rect(...)

I can't find the place from where the callback is initiated, I only know it is called by invoke_callback() in vispy/event.py from EventEmitter class

In p5 where this call back to call on_resize() in base.py is initiated, any heads up where I can look into ?

[arihantparsoya]

The on_resize() function is called whenever the width and height of the sketch are reset: https://github.com/p5py/p5/blob/master/p5/sketch/userspace.py#L186

[arihantparsoya]

Shapes inside setup are drawn correctly if you remove size(100, 100) in setup()
Maybe, the shape rect((0,0),50) is drawn on default canvas of 360 * 360 but size(width,height) in setup() is overwiting and clearing the default canvas, so it shows nothing

Yes, somehow the flush_geometry() (https://github.com/p5py/p5/blob/master/p5/sketch/renderer2d.py#L203) is called before the on_resize() function when size() is used. I printed the order in which the functions are called:

When size() is called

clear
clear
clear
before setup: https://github.com/p5py/p5/blob/master/p5/sketch/base.py#L96
clear
clear
clear
flush geometry -> flush_geometry is called before the setup is complete
clear -> Removes all the rendered shapes
clear
setup done
flush geometry

When the size() is not called:

clear
clear
before setup
clear
setup done
flush geometry -> flush geometry should be called after the setup is done

[tushar5526]

I am a little confused with clear and flush_geometry, can't figure out when exactly the output window is cleared because clear and flush geometry is called continuously, can anyone give me a heads-up

Attached the output files when size() is called and size() is not called along with their calling parent functions till the top layer, take a look

When size is not called
when size is called

[tushar5526]

@parsoyaarihant

clear
clear
clear
(360, 360) = > default size ( print(self.size) in on_timer() )
setup started = > setup 
clear
setup finished = > finished correctly
flush geometry = > flushed after setup
clear
clear
clear
clear
flush geometry
clear
(50, 50) = > size is changed now when "vispy's event loop" detect changes
flush geometry
clear
(50, 50)
flush geometry 

Can you recheck the calls you mentioned above, these were the calls I got for the demo code above. I think the problem is possibly due to how on_resize() event occurs in vispy. Initially the width and height is set to 360,360 and when we use size() inside setup() it changes the canvas.size, variable but it do not change the window's size until the main event loop detects the changes, and this also calls the def on _resize() in base.py which clears and resets the view.